Air-cooled gas turbine



J y 'r. M. MCKENZIE, JR 2,445,837

AIR .COOLED GAS TURBINE Filed Aug. 24, 1946 2 Sheets- Sheet 1 l B a WWWJuly 27, 1948. T. M. MCKENZIE, JR

AIR COOLED GAS TURBINE 2 Sheets-Sheep 2 Filed Aug. 24, 1946 nuannuflu Hv m M i w I part or this application:

. Patented July 27, 1948 UNITED STATES PATENT- orricr.

AIR-COOLED GAS TURBINE Thomas M. McKenzie, Jr., Hyattsville, Md.Application August 24, 1946, Serial No. 692,802

7 Claims. (CI. 60-41) This invention relates to improvements inaircooled gas turbines.

An object of theinvention is to provide an improved impulse typeair-cooled gas turbine.

- Another object or the invention is to provide signed to give the leastwind'resistance possible at I the tips of the blades, which wouldotherwise be in danger of shearing 0115 due to windage.

' A still further object oi'the invention is to provide a multiple stageimpulse type air-cooled gas turbine having automatically controlledmeans for cooling the turbine blades and the labyrinth packings aboutthe hollow shaft and between the drums of the turbine, with an aircompressor being connected to the combustion chamber of said turbine andhaving lines or pipes with reducing valves connected with said labyrinthpackings 30 at the opposite sides of said rings to prevent leak age ofcontaminated gases into the cleanair, and also to increase theefliciency of the turbine.

Other objects will appear as the description proceeds. v

In the accompanying drawings which form a V Figure 1 is a schematicvertical sectional view through the improved impulse type air-cooled gasturbine; Figure 2 is a plan view looking down on one 01' the turbinedrums and rings, the same being partly broken away to show thecross-sectional shape of the hollow turbine blades:

Figure 31s a vertical sectional view through one of the turbine drums,being partly broken away 'and in section to show the arrangement of theair-cooled turbine blades and holding ring;

, panying drawings to designate corresponding In carrying out theinvention, there is provided an improved impulse type air-cooled gasturbine I an improved multiple stage impulse type airhaving a casinggenerally denoted by the reference numeral I, and a longitudinallyextending hollow shaft 2 having flared ends 3 and 4 at its oppositeends, being adapted to receive the oppositely disposed funnel-shaped airinlet housings 5 and 6 whose reduced inner'ends 'l and I are supportedupon the frame members 9 and II disposed on the base standards II andI2.

The three stage impulse type air-cooled gas turbine islprovided with therotatably mounted drums l3, ll and I5, each of which is received in asuitable recess in the casing l, and are open at their central portionsto receive air from the air inlet passages or apertures, it formedthrough the wall of thehollow shaft 2.

Annular internal webs ll are formed in each drum II, II and i5, and areaperturedat It to allow air to pass therethrough' to the radiallyextending hollow turbine blades is supported about said drums andcooperating with the holding rings 20 which are labyrinth packed andported at 2| to hold the turbine blades in place and to suck the airinto the turbine blades.

The turbine blades is arcuately curved, of the drawings.

A combustion chamber 22 is secured to the end 01' the casing I by meansof the bolts 23 and connects through the nozzle 24 with the turbineblades on the first stage drum II, to direct the combusare transverselyand as clearly-shown in Figure 4 tion gases at an approximate pressureof 150 pounds against and through said blades. After the gases passthrough the blades on drum [3, the pressure will have dropped toapproximately 100 pounds to be discharged through the nozzle 25 drumItto and through the blades on the second stage The combustion gaseswill then drop to approximately pounds and be discharged 1 through thenozzle 26 to and through theblades on the third stage drum Ii, to beexhausted into Figure 4 is a plan view looking down on a hol- 50 theatmosphere or auxiliary heat transfer units where remaining heat may beutilized for other purposes. V

The air casing or chamber 21 will be formed about the holding rings 20to receive the air sucked through the turbine blades and rings 2!, to beled through the pipe 28 into the funnel 2! on the air inlet pipe 30connected with the air compressor 3L. The air compressor II will beconnected by meansof the pipe 32 with the out the followingspecification and the accomcombustion chamber to discharge air theretoat from a suitable fuel pump and supply tank (not shown).

A compressed air pipe line 35 will branch from a the air pipe 32, andwill be provided with the three reducing valves 35, 31 and 38, which inturn have pipe lines extending to the combustion chamber side of thelabyrinth packing 39 on the first stage holding ring 20 and to thelabyrinth packing 40 on the hollow shaft 2, to the adjacent sides of thelabyrinth packings ll and 42 on the holding ring 20 on the second stageand to the labyrinth packing 43 on said hollow shaft, and finally to thelabyrinth packings l4 and 45 on the holding ring 20 on the third stageand to the labyrinth packing 46 on said hollow shaft 2.

As before mentioned, the combustion gases will reach the three stages ordrums at pressures of 150 pounds, 100 pounds and 50 pounds,respectively, while the reducing valves will direct the air at pressuresof 175 pounds, 125 pounds, 75 pounds and 25 pounds to the variouslabyrinth packings to oppose and preventany leakage of the contaminatedgases into the fresh air supply to the air compressor.

The entrance of air at atmospheric pressure into the opposite ends ofthe hollow shaft will be controlled vbythe butterfly valves 41 and 48connected by the arms 49 and 50 with the bellows type thermostats and52, which are in turn connected by means of the small pipes 58 and 54with the bulbs 55 and 56 extending through the walls of the air casingor chamber 21, whereby the temperature of the air which varies at theopposite ends of the air chamber will be kept at an approximately evenlevel. Coil springs 51 and 58 will be secured to the arms 49 to urge thebutterfly valves .41 and 45 toward their closed positions.

From the foregoing description, it will be apparent that the airpressure from the air compressor will always be materially more than thepressure of the combustion gases at the various stages of the turbinewhere the compressed air.

is led to the labyrinth packings, thereby forcing back and preventingthe contaminated combustion gases from entering into the fresh clean airwhich is fed back to theair compressor.

2. An impulse type air-cooled multiple stage gas turbinecomprising acasing, a. hollow shaft extending axially therethrough; a combustionchamber on said casing, multiple stage turbine drums rotatably mountedin said casing having communication with said hollow shaft, hollowturbine blades supported by said drums, ported holding rings disposedabout the outer ends of said turbine blades, an air compartment aboutsaid rings, controlled means for cooling said turbine blades, andlabyrinth packing at the opposite sides of said drums and said rings.

3. An impulse type air-cooled multiple stage gas turbine comprising acasing, a hollow shaft extending axially therethrough, a combustionchamber on said casing, multiple stage turbine drums rotatably mountedin said casing having communication with said hollow shaft, hollowturbine blades supported by said drums, ported holding rings disposedabout the outer ends of said turbine blades, an 'air compartment aboutsaid rings, controlled means for cooling said A suitable drive (notshown) will be connected with the hollow shaft upon which the turbinedrums are mounted to operate any desired mechanism. 1

While the preferred embodiment of the instant invention has beenillustrated and described, it

will be understood that it is not intended to limit the scope of theinvention thereto, as many minor changes in detail of construction maybe resorted to without departure from the spirit of a turbine blades,labyrinth packings at the opposite sides of said drums and said rings,and an air compressor having its inlet connected with said aircompartment and its outlet connected with said combustion chamber.

4. An impulse type air-cooled multiple stage gas turbine comprising acasing, a hollow shaft extending axially therethrough, a combustionchamber on said casing, multiple stage turbine drums rotatably mountedin said casing having communication with said hollow shaft, hollowturbine blades supported by said drums, ported holding rings disposedabout the outer ends of said turbine blades, an air compartment aboutsaid rings, controlled means for cooling said turbine blades, labyrinthpackings at the opposite sides of said drums and said rings, an aircompressor having its inlet connected with said air compartment and itsoutlet connected with said.

combustion chamber, and means connected with said air compressor forcooling said labyrinth packings and to prevent leakage of hotcontaminated gases into the clean air supply.

5. An impulse type air-cooled multiple stage gas turbine comprising acasing, a hollow shaft extending axially therethrough, a combustionchamber on said casing, multiple stage turbine drums rotatably mountedin said casing having communication with said hollow shaft, hollowturbine blades supported by said drums, ported holding rings disposedabout the outer ends of said turbine blades, an air compartment aboutsaid rings, controlled means for cooling said turbine blades, labyrinthpackings at the opposite sides of said drums and said rings, an aircompressor having its inlet connected with said air compartment and itsoutlet connected with said combustion chamber, means connected with saidair compressor for cooling said labyrinth packings, and valves in theends of said hollow'shaft hollow turbine blades supported by said drums,

ported holding rings sposed about the outer ends of said turbine blades,an air compartment about said rings, and controlled means for coolingsaid turbine blades,

to control the admission of air to and through said turbine drums andblades.

6. An impulse type air-cooled multiple stage gas turbine comprising acasing, a hollow shaft extending axially therethrough, a combustionchamber on said casing, multiple stage turbine drums rotatably mountedin said casing having communication with said hollow shaft, hollowturbine blades supported by said drums, ported holding rings disposedabout the outer ends of said turbine blades, an air compartment aboutsaid rings, controlled means for cooling said turbine blades, labyrinthpackings at the opposite sides of said drums and said rings, an aircompressor having its inlet connected with said air compartment and itsoutlet connected with said combustion chamber, means connected with saidair compressor for cooling said labyrinth packings, valves in the endsof said hollow shaft to control the admission of air to and through saidturbine drums and blades, and bulbs in said air compartment connectedwith thermostats for controlling said valves and the admission of air 10to and through said turbine drums and blades.

7. The subject matter as claimed in claim 4, and air lines from said aircompressor having reducing valves connected with said labyrinth packingsfor directing a pressure thereto greater than the pressure of. thecombustion gases to prevent the contaminated gases from entering the aircompressor with the fresh air.

THOMAS M. MCKENZIE, JR.

